Multiphase pump

ABSTRACT

A multiphase pump includes a master cylinder having a first port adjacent to a first end of the master cylinder, and a second port adjacent to a second end of the master cylinder connected to a source of hydraulic fluid. A master piston is positioned within the master cylinder. A slave cylinder is adjacent to each of the first and second ends of the master cylinder. Each slave cylinder has a first input port and a first output port adjacent to a first end of each slave cylinder, and a second input port and a second output port adjacent to a second end of each slave cylinder. Each first input port and second input port is adapted to connect to a source of gas to be compressed. A slave piston is positioned within each slave cylinder and is connected to the master cylinder such that movement of the master piston results in movement of each slave piston.

FIELD

The present application relates to a multiphase pump.

BACKGROUND

U.S. Pat. No. 6,568,911 describes a hydraulic compressor arrangement for compressing gas.

SUMMARY

There is provided a multiphase pump includes a master cylinder having a first port adjacent to a first end of the master cylinder, and a second port adjacent to a second end of the master cylinder. Each of the first port and the second port are connected to a source of hydraulic fluid. A master piston is positioned within the master cylinder. A slave cylinder is adjacent to each of the first end of the master cylinder and the second end of the master cylinder. Each slave cylinder has a first input port and a first output port adjacent to a first end of each slave cylinder, and a second input port and a second output port adjacent to a second end of each slave cylinder. Each first input port and second input port is adapted to connect to a source of gas to be compressed. A slave piston is positioned within each slave cylinder. Each slave piston is connected to the master cylinder such that movement of the master piston results in movement of each slave piston.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein:

FIG. 1 is a schematic view of the multiphase pump in a first position.

FIG. 2 is a schematic view of the multiphase pump in a second position.

FIG. 3 is a schematic view of an alternate multiphase pump.

DETAILED DESCRIPTION

A multiphase pump, generally identified by reference numeral 10, will now be described with reference to FIGS. 1 and 2.

Structure and Relationship of Parts:

Referring to FIG. 1, multiphase pump 10 includes a master cylinder 12 with a master piston 13 within. Master cylinder 12 has a first port 14 adjacent to a first end 16, and a second port 18 adjacent to a second end 20. First port 14 and second port 18 are connected to a source 22 of hydraulic fluid, which includes a power source for applying pressure to circulate hydraulic fluid to and from first and second ports 14 and 18. In some situations, it may be convenient to use an existing power source to circulate hydraulic fluid, such as an engine driving a pump for a well.

There is also a slave cylinder 30 with a slave piston 31 within positioned adjacent to each of first end 16 of master cylinder 12 and second end 20 of master cylinder 12. Each slave cylinder 30 has a first input port 32 and a first output port 34 adjacent to a first end 36, and a second input port 38 and a second output port 40 adjacent to a second end 42. Each input and output port 32, 34, 38 and 40 are one way valves to allow a gas to be compressed to enter input ports 32 and 38, and exit output ports 34 and 40. Each input port 32 and 38 is adapted to connect to a source of fluid 43 to be pumped, such as a wellhead 44, and each output port 34 and 40 is connected to a transport or storage system, such as a pipeline 46 or a storage tank. The design of multiphase pump allows it to be used for various fluids. Thus, it may be connected to a natural gas-producing wellhead, in which case it acts as a hydraulic compressor. It may also be used to pump liquids, or a combination of fluids. When pumping fluids from a wellhead, there will often be a separator package (not shown) between output ports 34 and 40 and pipeline 46 or storage tank to removed the unwanted phase.

Slave piston 31 is connected to master cylinder 12 by a rod 48 or other rigid connector, such that movement of master piston 13 results in movement of each slave piston 31. Seals 50 are used to prevent hydraulic fluid or gas from passing between master cylinder 12 and slave cylinders 30.

Operation:

As hydraulic fluid is pumped into first port 14, master piston 13 is moved from first end 16, as shown in FIG. 1, toward second end 18, as shown in FIG. 2. Rod 48 causes each slave piston 31 to move accordingly. Master piston 13 and slave pistons 31 are moved back by pumping hydraulic fluid into second port 18. Because of a slave cylinder 30 being positioned at each end of master cylinder 12, and each slave cylinder having two input ports 32 and 38 and two output ports 34 and 40, one cycle of master piston 13 results in four pump strokes.

Variations:

Referring to FIGS. 1 and 2, the diameter of master cylinder 12 is less than the diameter of slave cylinder 30. This is particularly useful when pump 10 is used as a compressor, as it allows more gas to be compressed with a smaller volume of hydraulic fluid being pumped to and from master cylinder 12 than would otherwise be the case. Multiphase pump 10 may also be designed with different relative volumes of slave cylinder 30 and master cylinders 12. For example, as shown in FIG. 3, master cylinder 12 may be larger than slave cylinders 30, which would be useful for pumping heavy fluids, when there is a greater force is to be overcome, etc.

Multiphase pump 10 may also be used for other pumping and compression applications, for example, it may be used for pumping water, or it may be positioned downhole to pump fluid. If it is used as a downhole pump, it is preferred to design pump 10 that rod 48 be hollow, and that output ports 34 and 40 be located on rod 48, such that fluid is pumped from slave cylinders 30 through rod 48 to surface.

Advantages:

Multiphase pump 10 may be used to pump liquids, gases, or combinations thereof. When gases are pumped, multiphase pump 10 may act as a hydraulic compressor. Furthermore, the mechanical advantage of pump 10 may be changed by set by simply designing pump 10 with a larger smaller slave cylinders 30 relative to master cylinder 12.

It has also been found that it is possible to obtain full strokes in slave cylinders 30 without having to worry about a blowout by limiting the maximum hydraulic pressure applied to master cylinder 12.

In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiment without departing from the spirit and scope defined in the Claims. 

1. A multiphase pump, comprising: a master cylinder having a first port adjacent to a first end of the master cylinder, and a second port adjacent to a second end of the master cylinder, each of the first port and the second port being connected to a source of hydraulic fluid; a master piston positioned within the master cylinder; a slave cylinder adjacent to each of the first end of the master cylinder and the second end of the master cylinder, each slave cylinder having a first input port and a first output port adjacent to a first end of each slave cylinder, and a second input port and a second output port adjacent to a second end of each slave cylinder, each first input port and second input port being adapted to connect to a source of gas to be compressed; and a slave piston positioned within each slave cylinder, each slave piston being connected to the master cylinder such that movement of the master piston results in movement of each slave piston.
 2. The multiphase pump of claim 1, wherein the diameter of the master cylinder is less than the diameter of the slave cylinders.
 3. The multiphase pump of claim 1, wherein the diameter of the master cylinder is greater than the diameter of the slave cylinders.
 4. The multiphase pump of claim 1, wherein one cycle of the master piston results in four compression strokes.
 5. The multiphase pump of claim 1, wherein each of the input ports and the output ports are one-way valves.
 6. The multiphase pump of claim 1, wherein each first input port and second input port is adapted to connect to a natural gas-producing well.
 7. The multiphase pump of claim 1, wherein the each of the first outputs and the second outputs are adapted to connect to a natural gas storage tank or a natural gas pipeline.
 8. The multiphase pump of claim 7, wherein the source of hydraulic fluid is driven by the power source for the natural gas-producing well.
 9. A multiphase pump, comprising: a master cylinder having a first port adjacent to a first end of the master cylinder, and a second port adjacent to a second end of the master cylinder, each of the first port and the second port being connected to a source of hydraulic fluid; a master piston positioned within the master cylinder, the position of the master cylinder being controlled by the source of hydraulic fluid; a slave cylinder adjacent to each of the first end of the master cylinder and the second end of the master cylinder, the diameter of each slave cylinder being greater than the diameter of the master cylinder, each slave cylinder having a first input port and a first output port adjacent to a first end of each slave cylinder, and a second input port and a second output port adjacent to a second end of each slave cylinder, each first input port, second input port, first output port and second output port being one-way valves, each first input port and second input port being adapted to connect to a natural gas-producing well, each first output port and each second output port being adapted to connect to a natural gas storage tank or a natural gas pipeline; and a slave piston positioned within each slave cylinder, each slave piston being connected to the master cylinder such that movement of the master piston results in movement of each slave piston, and such that one cycle of the master piston results in four compression strokes. 